Ferromagnetic Instability in AFe4Sb12 (A = Ca, Sr, and Ba)

TL;DR

This study investigates the magnetic, transport, and thermal properties of AFe4Sb12 compounds (A = Ca, Sr, Ba), revealing nearly ferromagnetic behavior and weak ferromagnetism at low temperatures.

Contribution

It provides experimental evidence of ferromagnetic instability and weak ferromagnetism in AFe4Sb12 compounds, expanding understanding of their magnetic properties.

Findings

All compounds show a susceptibility and thermopower maximum at 50 K.

Large electronic specific heat coefficient of 100 mJ/mol K2 observed.

Remanent magnetic moments of ~10^-3 μB/Fe detected below certain temperatures.

Abstract

Magnetic, transport and thermal properties of AFe4Sb12 (A = Ca, Sr, Ba) are reported. All three compounds show a maximum in both the magnetic susceptibility and thermopower at 50 K, and a large electronic specific heat coefficient of 100 mJ/mol K2. These properties are the characteristics of a nearly ferromagnetic metal. Furthermore, a remanent moment of the order of 10-3muB/Fe was observed below 54, 48, and 40 K for A = Ca, Sr, and Ba, respectively. The volume fraction of the ferromagnetic component was estimated to be 10-20% by zero-field muSR measurements.